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Scientists have come up with a way to perfectly radiate energy into any room, thanks to a sci-fi type device they call “anti-laser”.
The idea is simple: just as a laser emits particles of light, or photons, one after the other in a clean and tidy row, an anti-laser sucks in the photons one after the other in reverse order. Researchers have long speculated that a device like this could make charging wires and cables a thing of the past, allowing people to invisibly stream power across a room to a laptop or phone and power it without plugging it in. But although basic anti-lasers have tested this before, the real world isn’t as clean and tidy as a laser pointed at a stationary receiver in a lab. Electronics move, objects intrude, walls reflect energy in unexpected ways. The new anti-laser demonstrated in this experiment explains this and receives scattered energy radiated around a space in an unpredictable pattern, still receiving 99.996% of the power sent.
The formal term for the method used is “consistent perfect absorption” (CPA). CPA uses one machine to send energy across the room and another (the “anti-laser”) to suck it in. Previous CPA experiments, the researchers wrote in an article published Nov.17 in the journal Nature Communications, they were exciting but had a fundamental limit: the direction of time. The experiments only worked in situations where time could easily flow backwards as well as forwards, something that rarely exists in our daily life.
Related: 8 ways you can see Einstein’s theory of relativity in real life
The simplest model of an anti-laser setup, involving a laser pointer firing photons one after another into a receiver swallowing them, would look basically the same if playing a tape of its action forward or backward: Photon exits one device, travels through space and enters the other device. Configurations like this are said, in physical terms, to have “time reversal symmetry”. Time reversal symmetry only manifests itself in systems without much entropy, or the inherent tendency of systems to descend into disorder.
Until now, even the most complex CPA experiments have had a time reversal symmetry. Some were more complex than the laser pointer aimed at a receiver. But even complicated designs have that symmetry if they’re set up in such a way that the process can be reversed.
(Here’s an example of how a complicated event can be symmetrical to time reversal: imagine a videotape of a hobbyist collecting Lego pieces from a well-organized case and using them to build a model of the Eiffel Tower. but the tape would record where each piece went, so playing the tape in reverse would show the hobbyist to simply take the pieces apart and arrange them again.
But for this new work, the researchers used magnetic fields push photons so aggressively that they lose the time reversal symmetry. The process of transferring power – shooting photons – was like mixing soup: it doesn’t work backwards. (Imagine trying to drain the soup.) But the device was still receiving power.
This “demonstrates that the CPA concept goes far beyond its initial conception of” inverse time laser “,” the researchers wrote in their paper, suggesting that it may someday have practical real-world applications. This is because the real world is not as clean as a time-reversible laboratory experiment. It is messy and unpredictable and never reversible over time in the long term. In order for the CPA to work in these difficult conditions, it must be able to deal with it.
The researchers realized this non-temporal inverse CPA in two experimental setups, both using microwave power. The first was a “labyrinth” of wires that photons had to navigate to reach a receiver. The second was a small irregular “brass cavity” with a receiver in the middle, which the photons reached after scattering and traversing the open space in the cavity.
To achieve this, the researchers emitted microwaves of different properties and tested which combination of frequencies, amplitudes and phases (three characteristics of any electromagnetic wave) were most likely to land on the receiver and be absorbed, even after passing through magnetic fields. . and the labyrinth or irregular open space. In any case, they determined an ideal “tuning” of the microwave emitter which caused the absorption of most microwaves (99.999% in the maze, 99.996% in the open space). In real-world applications (such as your living room), the emitter would test and retest the different frequencies, amplitudes and phases to transfer photons to its receiver.
There are three main potential applications for this technology. The first is remote wireless energy transfer, the researchers wrote. (Goodbye to connecting your laptop.) Another is a sensing device that can detect subtle changes in any room where photons are scattered. (Imagine a security camera that can hear an intruder moving across a room.)
The third is a messaging system that can securely transfer information to a hidden receiver; signals sent via CPA could use ever-changing tuning numbers as a kind of password to encrypt data. Only the recipient or someone who knew the exact behavior of the recipient from moment to moment could decrypt the message.
Any such use in the real world is still a long way off. But this experiment shows that they are at least possible, the researchers wrote.
Originally published on LiveScience.
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